cmake -LAH: list CMake cache variables and options of a project

To list the cache variables of a configured CMake project, run cmake -L -N build. -L lists every cache entry that is neither advanced nor internal, -N only reads CMakeCache.txt without configuring again, and adding A and H (-LAH) also shows advanced variables and each variable's help text. These are the values you can change with -D NAME=value.

The variants

List the options of a project

cat > CMakeLists.txt <<'EOF'
cmake_minimum_required(VERSION 3.20)
project(demo NONE)
option(WITH_DOCS "Build the documentation" ON)
set(LOG_LEVEL "info" CACHE STRING "Default log level")
set_property(CACHE LOG_LEVEL PROPERTY STRINGS debug info warn)
set(TOOL_PATH "" CACHE FILEPATH "Path to an external tool")
mark_as_advanced(TOOL_PATH)
set(NOT_CACHED "x")
EOF
cmake() { uv run -q --no-project --python 3.13 --with cmake==4.4.4 --with ninja==1.13.0 cmake "$@"; }
cmake -S . -B build -G Ninja > /dev/null
echo '--- -L';  cmake -L -N build | grep -v '^CMAKE_INSTALL_PREFIX'
echo '--- -LH'; cmake -LH -N build | grep -A1 'log level'
echo '--- -LA, only TOOL_PATH'; cmake -LA -N build | grep TOOL_PATH
echo '--- -LR'; cmake -LR '^WITH_' -N build

--- -L
-- Cache values
LOG_LEVEL:STRING=info
WITH_DOCS:BOOL=ON
--- -LH
// Default log level
LOG_LEVEL:STRING=info
--- -LA, only TOOL_PATH
TOOL_PATH:FILEPATH=
--- -LR
-- Cache values
WITH_DOCS:BOOL=ON

The first listing leaves out CMAKE_INSTALL_PREFIX, which every project has and whose default differs per OS (see cmake --install --prefix). TOOL_PATH appears only with A because mark_as_advanced() hides it, and NOT_CACHED never appears: a plain set() is not a cache entry. The type after the colon (BOOL, STRING, PATH, FILEPATH) is what option() or set(... CACHE TYPE ...) declared.

Change a value and check it

cmake -S . -B build -DLOG_LEVEL=debug -DWITH_DOCS=OFF
cmake -LR '^(LOG_LEVEL|WITH_DOCS)$' -N build

A value set with -D is written to the cache and kept for every later configure of that build directory, even when you no longer pass it. To return to the project defaults, remove the entry with -U NAME or reconfigure with --fresh, see cmake clean build.

Other ways to read the cache

• ccmake build (Linux, macOS) and cmake-gui show the same list in an editor; press t in ccmake to toggle advanced entries.
• grep '^NAME' build/CMakeCache.txt reads the file directly; the cache also holds INTERNAL entries that -L never shows.
• Inside CMakeLists.txt, message(STATUS "LOG_LEVEL=${LOG_LEVEL}") prints the value during configure.

Pitfalls

• Without -N, -L reconfigures. On a project that fails to configure you get the error instead of the list; add -N to read the existing cache.
• Wrong directory. -N on a directory without CMakeCache.txt lists nothing useful; pass the build directory, not the source directory.
• Build type. A CMAKE_BUILD_TYPE value in the list only matters with single-config generators (Ninja, Makefiles); multi-config generators such as Visual Studio pick the configuration at build time, see CMAKE_BUILD_TYPE.

FAQ